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BiFeO3–BaTiO3 (BF–BT) ceramics with high Curie temperature and excellent piezoelectric coefficient are expected to be applied in high-temperature piezoelectric sensors and actuators. However, its resistivity decreases rapidly with temperature and impedes its further applications. Moreover, normal methods such as doping modification cannot address this issue. In the present work, bismuth layered Bi4Ti2.93(Zn1/3Nb2/3)0.07O12 (BIT) and perovskite 0.36BiScO3-0.64PbTiO3 (BSPT) ceramics were selected as insulating layers and were, respectively, sintered with 0.7BF–0.3BT ceramics to form laminated ceramics. The heterojunction structures effectively prevent carrier migration, and both resistivities of BIT and BSPT laminated ceramics were increased from 106 to 108−9 Ω cm at 300 °C. In addition, piezoelectric properties of the BSPT-type laminated ceramics are much higher than that of BF–BT ceramics, in which the bipolar strain was increased from 0.04% to 0.1% (4 kV/mm), and d33 was increased from 140 to 237 pC/N. Therefore, designing the insulating layer may be an effective method to realize the high-temperature application for BF–BT ceramics. [ABSTRACT FROM AUTHOR]

Piezoceramics with the formula Pb0.93Sr0.06Ba0.01(Mg1/3Nb2/3)0.035(Ni1/3Nb2/3)0.2 (Sb1/2Nb1/2)0.015(ZrxTi1−x)0.75O3 + 0.5 wt. % Li2CO3, where x = 0.51, 0.50, 0.49, 0.48, 0.47, and 0.46, have been made using the one-step solid-state method. The phase structure and electrical properties were systematically investigated in the quinary system. Here, the crystalline structure transformed gradually from the rhombohedral to tetragonal phase with decreasing Zr content. More importantly, the effective piezoelectric coefficient d33* of the ceramics demonstrates an excellent thermal stability below the Curie temperature. Meanwhile, piezoelectric ceramics with x = 0.49 exhibited the extraordinary electrical properties near the morphotropic phase boundary. A huge piezoelectric coefficient d33 = 853 pC/N, high Curie temperature TC = 152 °C, and the electromechanical coupling coefficients kp = 67.4%, kt = 63.5%, and k33 = 67.4% were obtained at the composition of x = 0.49, which may lead a promising future for the transducer applications. [ABSTRACT FROM AUTHOR]

In this paper, new series of high temperature piezoelectric ceramics consisting of (0.975- x)BiScO 3 - x PbTiO 3 -0.025 Pb(Sn 1/3 Nb 2/3)O 3 (BS- x PT-0.025PSN), have been fabricated and investigated in detail. The phase structure analysis and electrical properties characterization at room temperature demonstrate the MPB composition is BS-0.62PT-0.025PSN with the optimum piezoelectric performance (d 33 523 pC/N, large-signal d 33 * 734 p.m./V, and k p 54.6%), which are superior than the unmodified BS-PT ceramics. Interestingly, the in situ electromechanical coupling properties exhibits good stability with the variation lower 5% as the temperature increasing from room temperature to 300 °C and the d 33 * reaches the maxima of 1413 p.m./V at 200 °C, and remains 743 p.m./V even at 300 °C, showing the BS-0.62PT-0.025PSN ceramics potential for high temperature piezoelectric actuator application together with the Curie temperature of 418 °C and the high temperature annealing stabilities. Then a 10-layer stack-type piezoelectric actuator was designed and fabricated based on the BS-0.62PT-0.025PSN ceramics, which can be operated steadily up to 200 °C and produces a displacement of 24 μm under the driven electric field. The maximum displacement 32.4 μm of the actuator was obtained at the testing temperature of 150 °C, far more than that of the value at the room temperature. The BS-0.62 PT-PSN ceramics and their stack-type piezoelectric actuator maybe a strong supplement to satisfy the urgent demand for high temperature piezoelectric actuator. [ABSTRACT FROM AUTHOR]

To design novel materials suitable for high-temperature electromechanical applications, a bismuth-based ternary solid solution system, (1- x - y)BiScO 3 - y Pb(Sc 1/2 Nb 1/2)O 3 - x PbTiO 3 , with compositions situated around the morphotropic phase boundary, were designed and synthesized in the form of ceramic. The crystal structure, microstructure, dielectric, ferroelectric and piezoelectric properties, and the local polar domain structure of the ceramics were investigated in detail. The examined ceramics exhibit large grain sizes ranging from 20 μm to 45 μm, along with noteworthy characteristics, including a relatively large strain of 0.21 %, a high large-signal piezoelectric coefficient (d 33 * = 368 pm/V), a low dielectric loss (tanδ = 1.7 %), and a high Curie temperature (T C ∼ 423 °C). These enhanced properties signify the suitability of the designed ternary ceramics for future high-temperature electromechanical applications. This work demonstrates an effective approach for designing ferro-/piezoelectric materials characterized by substantial strain and low dielectric loss. [ABSTRACT FROM AUTHOR]

Na 0.25 K 0.25 Bi 2.5 Nb 2 O 9 -based piezoelectric ceramics are potential candidates for high-temperature applications where improving piezoelectric properties is an urgent issue. In this work, significantly improved piezoelectric properties and thermal stability of Na 0.25 K 0.25 Bi 2.5- x Ce x Nb 2- y W y O 9 (abbreviated NKB 2.5- x C x N 2- y W y , x = 0.03, y = 0.01, y = 0.03, y = 0.05) ceramics were obtained through Ce and W co-doping and using a traditional solid-state technique. The optimal composition of NaKBi 2.47 Ce 0.03 Nb 1.99 W 0.01 O 9 exhibits a large piezoelectric coefficient d 33 of 23.1 pC/N, maintains a high Curie temperature T c of 690 °C, and a low tanδ of 0.006. The increase of d 33 may be attributed to the structure distortion, the micro-sized domains, and the high-density domain walls. More importantly, its d 33 value maintains 86 % of the initial value after being annealed at 650 °C for 2 h, whereas only 65 % for the undoped sample under the same conditions, indicating an obviously improved thermal stability. This work provides a new idea for improving piezoelectric properties and thermal stability of Na 0.25 K 0.25 Bi 2.5 Nb 2 O 9 -based piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Bi 3- x Ce x TiNbO 9 (BTN-100 x Ce, x = 0, 0.01, 0.03, 0.05, 0.07, 0.09, 0.11) piezoelectric ceramics with ultra-high Curie temperature were fabricated by a solid-state sintering method, and the effect of Ce doping on the structure, dielectric and piezoelectric properties of the ceramics was investigated. All ceramic samples possess a single Aurivillius phase and Ce ions enter both A- and B-sites. Dense microscopic morphology with a remarkable decrease of grain size can be observed due to Ce doping. The resistivity markedly increases after Ce modification, and a significantly enhanced piezoelectric constant d 33 of 17.1 pC/N can be achieved in the optimized BTN-7Ce ceramics, which is nearly 6 times that of pure Bi 3 TiNbO 9 (d 33 ≈ 3 pC/N). In addition to ultra-high Curie temperature (T C = 886.5 °C) and relatively high resistivity (ρ = 1.2 × 106 Ω cm @ 500 °C), the BTN-7Ce ceramics should be very promising for piezoelectric sensor under the application in high temperature conditions. [ABSTRACT FROM AUTHOR]

The enhanced high-power performance of 0.93 Pb(Zr 1-x Ti x)O 3 -0.05 Pb(Mn 1/3 Sb 2/3)O 3 -0.02 Pb(Sc 1/2 Nb 1/2)O 3 (x = 0.48, 0.50, 0.52, 0.54, 0.56) piezoelectric ceramics (PZT-PMS-PSN) has been achieved with notable improvement in the piezoelectric coefficient (d 33). The presence of the monoclinic phase (C c) has led to an increase in d 33 from 214 pC N−1 to 315 pC N−1. Therefore, the composition 0.93 Pb(Zr 0.48 Ti 0.52)O 3 -0.05 Pb(Mn 1/3 Sb 2/3)O 3 -0.02 Pb(Sc 1/2 Nb 1/2)O 3 exhibits excellent mechanical and electrical parameters: a d 33 value of 315 pC N−1, a high mechanical quality factor of 1578, an electromechanical coupling factor k p of 52 %, and a low dielectric loss tanδ of only 0.288 %. Additionally, this ceramic exhibits a significantly high Curie temperature (T c), reaching up to 328 °C which stabilizes its ferroelectric phase. Moreover, the phase transition of PZT-PMS-PSN ceramics from rhombohedral to tetragonal phase was investigated by X-ray diffraction, Raman scattering, Piezo-response force microscopy. [ABSTRACT FROM AUTHOR]

In this study, we investigated the phase structure, Curie temperature, dielectric properties, piezoelectricity, and energy-storage properties of BiFeO 3 (BFO)-modified (Ba 0.95 Ca 0.05) (Ti 0.89 Sn 0.11)O 3 (BCTSO) ceramics using both experimental and theoretical methods. The results indicated that the lattice distortion and chaotic distribution of the local charge increased with the BFO content, resulting in a phase transition and transformation from a ferroelectric to a relaxing ferroelectric. First-principles calculations revealed that the Curie temperature decreased with increasing BFO content, primarily because of an increase in the ground state energy. The variation in the permittivity of the BCTSO- x BFO ceramics with temperature and frequency is affected by the phase structure and Maxwell-Wagner interface polarisation, respectively. The electrical modulus measurements indicated that BCTSO- x BFO exhibited non-Debye-type dielectric relaxation for x = 0.0, 0.1, and 0.5 %, whereas BCTSO- x BFO showed Debye-type dielectric relaxation for x = 0.9%. [ABSTRACT FROM AUTHOR]

Piezoceramics have long encountered difficulties in simultaneously attaining a high Curie temperature (T C) and extraordinary electrical characteristics due to the issue of thermal depolarization. To handle this, a novel 0.1 Pb(Yb 0.5 Nb 0.5)O 3 (PYN)–0.9 Pb(Hf 1−x Ti x)O 3 (PHT) + x mol%Ta 2 O 5 piezoelectric ceramic was prepared using solid-state sintering method. We developed a synergistic strategy in introducing local heterogeneity into the tetragonal phase, where doping with heterovalent Ta5+ ions significantly reduces the temperature dependence of PYN–PHT piezoelectric ceramics. The structure and electrical behavior of obtained ceramics were methodically investigated using various analytical approaches. Our innovative composition, PYN–PHT–0.6Ta, showcases tetragonal phases. It exhibits impressive results, such as a piezoelectric coefficient d 33 of 560 pC/N, an electromechanical coupling coefficient of 0.7 and a T C of 312.2 °C. Doping with Ta5+ ions unveils the formation of small size, mixed-state domain structure in enhancing piezoelectric and dielectric properties of ceramics. Additionally, the pinning effect of tetragonal phase contribute to the remarkable temperature stability (the variation in d 33 is only 6.03 % from 25 °C to 300 °C) of the material. Overall, the exceptional performance and high quality of PYN–PHT–xTa ceramics hold great promise for high-temperature application in future microdevices. [ABSTRACT FROM AUTHOR]

Bi 4 Ti 3- x (Mg 1/2 W 1/2) x O 12 (BTMW100 x) ceramics were synthesized using a direct reaction method combined with a two-step sintering technique. The study systematically investigated the effects of B-site equivalent substitution of (Mg 1/2 W 1/2)4+ on BTMW100 x ceramics. The experimental results indicate that an appropriate amount of (Mg 1/2 W 1/2)4+ doping effectively reduces grain thickness, enhances grain distribution uniformity, and decreases the concentration of oxygen vacancies. Consequently, these modifications lead to improved piezoelectric performance while maintaining a high Curie temperature. Notably, Bi 4 Ti 2.95 (Mg 1/2 W 1/2) 0.05 O 12 (BTMW5) ceramics exhibit excellent piezoelectric properties and thermal stability, with a piezoelectric coefficient of 23 pC/N and a Curie temperature of 683 °C. These findings suggest that BTMW5 ceramics are promising candidates for high-temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

The present research focuses on the electrical properties of lead-free piezoceramics (0.985- x)(K 0.485 Na 0.485 Li 0.03)(Nb 0.96 Sb 0.04)O 3 -0.015(Bi 0.5 Na 0.5)ZrO 3 - x SnO 2 (KNNLS-BNZ- x SnO 2 , x = 0.003, 0.006, 0.009, 0.012, and 0.015). This study examines the influence of varying SnO 2 doping levels on the microstructure and piezoelectric properties of the ceramics. All the ceramics prepared demonstrate pure perovskite structure without any secondary phases. The Rietveld refinement analysis of XRD data reveals the existence of multiphase evolution around room temperature. The tetragonality (c/a) and cell volume of the ceramics tend to rise with an increase in Sn4+ content, potentially leading to improved ferroelectric characteristics. The optimum values obtained were Curie temperature (T c) = 395 oC, remnant polarization (P r) = 21.07 μC/cm2, piezoelectric coefficient (d 33)=357 pC/N, piezoelectric voltage constant (g 33) = 24 × 10−3 Vm/N, and figure of merit (FOM off) = 10.34 pm2/N, corresponding to the ceramic doped with x = 0.012 SnO 2. The findings indicate that an optimal amount of Sn4+ in the host composition KNNLS-BNZ improves piezoelectric properties by constructing an R-O-T phase boundary near room temperature. This study suggests that the ceramic with x = 0.012 SnO 2 exhibits a favorably high T c coupled with an exceptional energy harvesting capability, making it a suitable candidate for energy harvesting applications. [ABSTRACT FROM AUTHOR]

In this work, an attempt is made for improving the piezoelectric properties of a lead-free (Na 0. 5 K 0. 4 8 5 Li 0. 0 1 5) (Nb 0. 9 8 V 0. 0 2) O3 ceramic system by doping manganese in it. The Rietveld analysis of XRD micrographs of the ceramics indicates the samples crystallizing into 99.86% of orthorhombic phase and very small traces of tetragonal phase around room temperature. The Curie temperature ( T c ) is hardly affected by the incorporation of Mn 4 + into the system. At the manganese concentration of 0.02 wt.%, the ceramic system attains the peak values in its density, dielectric constant at room temperature ( ε RT ), planar electromechanical coefficient ( k p) , piezoelectric coefficient ( d 3 3 ), and remnant polarization ( P r ). The optimum piezoelectric properties of k p = 4 3 % and d 3 3 = 1 9 3 pC/N are observed for this composition. The study reveals that the modification of (Na 0. 5 K 0. 4 8 5 Li 0. 0 1 5 ) (Nb 0. 9 8 V 0. 0 2) O3 with an appropriate quantity of Mn 4 + can produce the desired changes in the crystallographic properties and densification so as to eventually improve its piezoelectric properties. [ABSTRACT FROM AUTHOR]

This paper focuses on improving the electrical properties of 0.4CaBi 2 Nb 2 O 9 -0.6Na 0.5 Bi 2.5 Nb 2 O 9 piezoelectric ceramics through Gd doping. The effect of Gd3+ replacing Ca2+ and Na+ on the 0.4CaBi 2 Nb 2 O 9 -0.6Na 0.5 Bi 2.5 Nb 2 O 9 (0.4CBN-0.6NBN) piezoelectric ceramics was subjected to a comprehensive examination. The introduction of Gd3+ has led to the development of a pseudo-tetragonal phase, enhancing the polarization and strengthening the piezoelectric effect. Among the 0.4CBN-0.6NBN- x Gd (x = 0.00–0.05) ceramic samples, the sample at x = 0.03 that exhibits the best piezoelectric properties demonstrates a high Curie temperature of 849.7 °C, low dielectric loss (tan δ) of 1.295 % (at 550 °C), high DC resistivity (ρ DC) of 1.58 × 108 Ω‧cm (at 500 °C), and a high d 33 value of 17.3 pC/N. Following annealing at 800 °C, its d 33 retains 94.2 % of its initial value. The improved electrical performances indicate that the Gd-doped 0.4CBN-0.6NBN ceramics hold a great deal of promise for high-temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

Achieving comprehensive improvement in both piezoelectric coefficient (d33) and mechanical quality factor (Qm) has become a key issue in the research of high‐power piezoelectric ceramics. Here, we focused on Mn‐doped Pb(In1/2Nb1/2)O3‐Pb(Sc1/2Nb1/2)O3‐PbTiO3 (PIN‐PSN‐PT) relaxor ferroelectric ceramics, where Mn‐doping is employed to enhance Qm. The effects of doping concentration and PT content on phase structure, ferroelectric, dielectric, and electromechanical properties were systematically studied. The well radius matching between Mn ions and B‐site ions facilitates the ion substitution and significantly increases the concentration of oxygen vacancies, thereby enhancing the domain wall pinning effect. A significantly weakened mutual constraint relationship between d33 and Qm is observed in the 2 mol% Mn‐doped PIN‐PSN‐PT ceramics with tetragonal phase, which exhibits Qm exceeding 3000 while maintaining d33 higher than 320 pC/N and Curie temperature higher than 300°C, leading to the vibration velocity over 1.15 m/s. Rayleigh analysis reveals the higher intrinsic piezoelectric response in high PT components compared to that in low PT components, which was thought to be the origin for the weakened mutual constraint relationship between d33 and Qm in tetragonal Mn‐doped PIN‐PSN‐PT ceramics. [ABSTRACT FROM AUTHOR]

High‐temperature piezoelectric ceramics with excellent piezoelectric properties are key materials for high‐temperature piezoelectric devices. In this context, bismuth titanate–niobate (Bi3TiNbO9) is one of the most promising candidates, owing to its high Curie temperature (TC) > 900°C. However, the relatively low piezoelectric response of prototype Bi3TiNbO9 does not satisfy the requirements of high‐precision and high‐sensitivity applications. Herein, chromium‐substituted Bi3TiNbO9 with a nominal composition, Bi3Ti1−xCrxNbO9 (BTN‐100xCr), was prepared using the solid‐state reaction method. Raman spectroscopy and X‐ray diffraction refinements revealed structural distortions induced by the substitution of chromium. Piezo‐response force microscopy and ferroelectric hysteresis loops showed facile polarization reversal and domain wall movement in chromium‐substituted Bi3TiNbO9. The resultant structural distortion and domain wall movement served as intrinsic and extrinsic contributions to the enhancement of the piezoelectric properties, respectively. Consequently, BTN‐1.5Cr exhibits a high piezoelectric constant (d33) of 17.7 pC/N, which is four times that of Bi3TiNbO9 (4.2 pC/N), a high TC of 908°C, and an excellent thermal stability of piezoelectric and electromechanical coupling properties up to 500°C. These results indicate that chromium substitution enhances the high‐temperature piezoelectric properties of Bi3TiNbO9, and chromium‐substituted Bi3TiNbO9 is a promising candidate for high‐temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

(K,Na)NbO3(KNN)-based ceramics are a promising lead-free piezoelectric material that could replace Pb(Zr1−xTix)O3-based materials due to their higher Curie temperature and superior electrical properties. However, the volatilization of sodium and potassium during conventional high-temperature sintering makes it difficult to obtain KNN ceramics with a dense structure and excellent electrical properties. Herein, a conventional solid-phase method combined with microwave sintering is applied for the preparation of KNN ceramics. The influence of the microwave sintering process on the microstructure and electrical properties of KNN ceramics were studied. The optimal microwave sintering conditions for KNN ceramics were determined to be 1100°C for 50 min. Under these conditions, the ceramic samples exhibited excellent ferroelectric properties, with the maximum polarization (Pmax) of 20.4 μC/cm2 and a remanent polarization (Pr) of 18.1 μC/cm2. Additionally, the samples demonstrated impressive piezoelectric properties, including the maximum electric field-induced strain (Smax) of 0.0251%, a dynamic piezoelectric coefficient (d33*) of 125.5 pm/V, and a piezoelectric coefficient (d33) of 109.8 pC/N. The study has important implications for the use of microwave sintering to achieve the densification of the ceramic with volatile elements such as KNN-based ceramics at lower sintering temperature and short sintering time. [ABSTRACT FROM AUTHOR]

To date, the enormous potential of lead‐free piezoceramics in ultrasonic transducers and micro‐actuators has driven extensive research and development. Although the piezoelectric coefficient (d33) of lead‐free ceramics is improved unprecedentedly, the breakthrough in comprehensive performance is still a key issue, one of which is the inverse relationship between d33 and Curie temperature (TC), and the other is the temperature stability of piezoelectricity. Here, based on the synergistic optimization of the chemical component modulation and texture technology, the high Curie temperature (≈365 °C), high piezoelectric properties (d33 ≈331 pC/N, d33* ≈561 pm V−1) and advanced piezoelectric temperature stability are realized by embedded PNRs in the conceived and prepared lead‐free single phase 0.96((K0.5Na0.5)(Nb0.98Ta0.02)O3)‐0.01(Bi(Ni0.67Nb0.33)O3)‐0.03(Bi0.5K0.5)HfO3 texture ceramics. The d33 changes by only 2.0% when the temperature is increased from 25 to 100 °C (≈10.0% to 200 °C), while the electrical strain (d33*) changes by only 4.2% when the temperature is increased from 25 to 175 °C (≈9.8% to 200 °C), which is comparable to the commercial lead‐based materials (i.e., PZT‐4). This work demonstrates significant progress in the comprehensive piezoelectric performance (especially the piezoelectric temperature stability) of lead‐free ceramics and inspires further attempts to achieve high‐temperature piezoelectric properties. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics with high electrical performances and high Curie temperature (Tc) act as key materials for numerous electromechanical devices such as transducers and actuators. Herein, we report a systematic investigation on the crystal structure, microstructure and electrical properties of Sr and La co-doped Pb(Mg1/3Nb2/3)O3–PbZrO3–PbTiO3 ceramics with a low Pb(Mg1/3Nb2/3)O3 content, namely, (Pb1−ySry)(Mg1/3Nb2/3)0.07ZrxTi0.93−xO3:zLa. With an increase in the Zr content (x value) from 0.49 to 0.53, its crystal structure evolved from a tetragonal phase to a rhombohedral phase, leading to not only a morphotropic phase boundary (MPB) at around x = 0.51 but also a monotonously decreasing Tc. Meanwhile, a change in either the Sr- or La-doping content (y and z values, respectively) in the range of y = 0.03–0.07 and z = 0.01–0.03 can slightly deviate the structure of MPB, resulting in a significant effect on its electrical properties. As the best results, the optimal composition of x = 0.51, y = 0.05, and z = 0.02 yielded peak electrical performance, with a related room temperature piezoelectric coefficient (d33) of 645 pC N−1, remanent polarization (Pr) of 33.5 μC cm−2, coercive field (Ec) of 8.6 kV cm−1, and Tc of 242 °C. Especially, its piezoelectric properties showed excellent temperature stability, and its d33 value decreased by only 3% from room temperature to 150 °C. This work not only provides an alternative piezoelectric ceramic with outstanding electrical performance for industrial applications, but also reveals a comprehensive perspective on the composition–structure–property relationship of doped Pb[(Mg1/3Nb2/3),Zr,Ti]O3, which is helpful for further work on piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

BiFeO 3 -BaTiO 3 (BF-BT) ceramics are an excellent choice for high-temperature lead-free piezoelectric ceramic due to their high Curie temperature and good piezoelectric properties, but the volatilization of Bi leads to the formation of A-site cationic vacancies and oxygen vacancies, culminating in heightened leakage currents and detrimental effects on piezoelectric properties. In this study, a chemical composition of 0.70Bi (1+ x) Fe 0·97 Al 0·03 O 3 -0.30BaTiO 3 ceramics, abbreviated as B 1+ x FA-BT, where 0 ≤ x ≤ 0.05, were synthesized, with special attention on the effects of Bi compensation and poling process on their insulation and piezoelectric properties. Due to the coexistence of R - PC phases and low leakage current, B 1+ x FA-BT ceramics exhibit excellent piezoelectric properties and high Curie temperature, among which the B 1.02 FA-BT ceramic boasts optimal overall properties: d 33 = 196 pC N−1, T C = 480 °C, k p = 34%, θ max = 49.5° and Q m = 32, under optimal poling parameters E p = 50 kV cm−1 and T p = 100 °C. The poling process is directly linked to the reorientation of domains, the redistribution of positive/negative space charge and the aggregation or injection of holes, which is achieved by tuning the poling field and temperature in a ceramic with optimal integrated piezoelectric properties. The poling process of BF-BT ceramics is significantly influenced by their leakage characteristics, which can have a significant impact on their overall performance. Optimizing electrical poling conditions and minimizing leakage current is crucial to achieving favorable piezoelectric properties in BF-BT ceramics with R - PC coexisting structures. [ABSTRACT FROM AUTHOR]

Sr2Nb2O7 (SNO) ceramics are promising high‐temperature piezoelectric materials due to their high Curie temperature (TC), good thermal stability, and high electrical resistivity. However, SNO presents low piezoelectric activity (d33 < 1 pC/N). Here, we successfully obtain textured SNO ceramics with an orientation factor of 0.86 by microstructure regulation. Saturated polarization‐electric loop was obtained in textured ceramic with remanent polarization Pr∼3.56 µC/cm2 and coercive field EC∼53.4 kV/cm. The piezoelectric coefficient d33 of the textured SNO ceramics is increased to 3.2 pC/N, with a high TC of 1342°C, while the low‐textured SNO ceramics exhibit no effective d33. Meanwhile, the piezoelectric coefficient d33 of textured SNO ceramics maintains consistency even at 1300°C, showing excellent thermal stability. The underlying mechanism driving this improvement is elucidated, emphasizing the facilitated domain‐wall motion enabled by the engineered microstructure. Furthermore, textured SNO ceramics exhibit high resistivity of 1.33 × 106 Ω⋅cm at 800°C. This study presents a simple and feasible microstructure engineering approach to enhance the piezoelectric properties of layer‐structured materials, offering valuable insights into the design and development of ceramics for diverse applications. Textured SNO ceramics achieved through microstructure regulation exhibit an orientation factor of 0.86, improved piezoelectric properties, and exceptional thermal stability with a high Curie temperature of 1342°C. These ceramics maintain high resistivity at elevated temperatures, demonstrating enhanced domain‐wall motion and a significant increase in the piezoelectric coefficient to 3.2 pC/N, even at 1300°C. [ABSTRACT FROM AUTHOR]

Real-time monitoring of structural health status is very important for supersonic aircraft, since the long-term operation in harsh service environments, such as high temperatures, can cause potential damage. Structural health monitoring (SHM) based on lamb wave has been approved to be a critical technique for the reliable operation of supersonic aircraft, but is limited by the operating temperature of conventional piezoelectric sensors, which makes it difficult to meet the high-temperature monitoring requirements. The BiFeO 3 –BaTiO 3 ceramics exhibit excellent piezoelectric properties and high Curie temperature (T c), making them promising for high-temperature SHM of supersonic aircraft. Here, we fabricated a piezoelectric sensor using 0.67BiFeO 3 -0.33BaTiO 3 -0.25%molMnO 2 (BF33BTMN-025) ceramic, which exhibits a piezoelectric charge constant (d 33) of 135 pC/N at room temperature and a T c of 448 °C. The BF33BTMN-025 ceramic sensor operates effectively at temperatures up to 200 °C and maintains stable damage monitoring sensitivity as well. Compared with Pb(Zr, Ti)O 3 (PZT), BaTiO 3 (BTO) and other piezoelectric sensors commonly used in SHM field, the BF33BTMN-025 ceramic sensor has a higher operating temperature and a comparable sensitivity. Our work demonstrates that the BF33BTMN-025 ceramic sensor can be employed as piezoelectric sensor for high-temperature SHM, which has a wide application potential in the field of real-time monitoring of supersonic aircraft. [ABSTRACT FROM AUTHOR]

The structural and various electrical properties of (1-x)Pb(Zr 1-z Ti z)O 3 -xPb(Zn 0.4 Ni 0.6) 1/3 Nb 2/3 O 3 [(1-x)P(Z 1-z T z)-xPZNN] piezoceramics have been systematically investigated to ascertain the compositions that manifest a rhombohedral-pseudocubic-tetragonal (R-PC-T) multistructure. Rietveld refinement results indicate that the pseudocubic (PC) structure observed in the (1-x)P(Z 1-z T z)-xPZNN piezoceramics closely resembles the Pm3m cubic structure. Nonetheless, the PC structure cannot be classified as cubic, given that piezoceramics exhibiting the PC structure also demonstrate ferroelectric and piezoelectric properties. The R-PC-T multistructure was detected in (1-x)P(Z 1-z T z)-xPZNN piezoceramics for compositions where 0.335 ≤ x ≤ 0.44, across various z values. Compositions exhibiting the R-PC-T multistructure are identified as particularly promising. Notably, the piezoceramic with the composition 0.58 P(Z 0.41 T 0.59)-0.42PZNN (x = 0.42 and z = 0.59) displayed remarkable piezoelectric properties, including a high piezoelectric charge constant, d 33 , of 825 pC/N, a coupling coefficient, k p , of 0.7, and a strain of 0.185% at 3.0 kV/mm, alongside a high Curie temperature (T C) of 240 °C. • (1-x)P(Z 1-z T z)-xPZNN piezoceramics with R-PC-T multistructure were identified. • The PC structure of (1-x)P(Z 1-z T z)-xPZNN ceramics is close to the Pm3m C structure. • Most piezoceramics with R-PC-T multistructure exhibit excellent piezoelectricity. • 0.58 P(Z 0.41 T 0.59)-0.42PZNN piezoceramic shows a large d 33 (825 pC/N) and k p (0.7). [ABSTRACT FROM AUTHOR]

Recent research has emphasized the investigation of BiFeO 3 –BaTiO 3 (BFO–BT) piezoelectric ceramics due to their elevated Curie temperature. Nevertheless, the substantial electrical conductivity of these ceramics poses practical challenges. This study evaluates the influence of post-annealing and manganese (Mn) doping on the conductivity, dielectric behavior, and ferroelectric properties of (1-x)BFO–xBT ceramics with a morphotropic phase boundary composition (x = 0.33). The results demonstrate that the conductivity of the ceramics in the as-sintered state is affected by Maxwell-Wagner effects arising from variations in conductivity at grain boundaries. Annealing under specific atmospheres indicates that the electrical conductivity is of the p-type, potentially associated with Fe4+ defects. Furthermore, annealing in a carefully controlled atmosphere or the introduction of Mn doping significantly alleviate these effects, leading to an enhancement in domain switching characteristics. The insights garnered from this investigation regarding annealing and doping have the potential to advance lead-free BFO–BT piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

The effect of calcination process on a phase evolution, a microstructure development and the piezoelectric properties were investigated in 0.75BiFeO 3 -0.25BaTiO 3 (0.75BF-0.25BT) ceramics. At the relatively low calcination temperatures of 600 °C–650 °C, a Bi 25 FeO 40 impurity phase was formed in addition to some unreacted raw materials and a perovskite phase. As the calcination temperature increased to the range of 700–900 °C, other intermediate phase BaBi 4 Ti 4 O 15 was formed concurrently with small amounts of unreacted BaCO 3 and perovskite matrix phase. At 950 °C a pure single perovskite phase of 0.75BF-0.25BT solid solution was observed. The sintered samples produced by using the raw powder calcined at a relatively low temperature of 600–900 °C showed a large fraction of pseudo-cubic relaxor phase (0.54–0.71 mass fraction) with the rest of a rhombohedral ferroelectric phase. They showed poor piezoelectric properties at sintering temperature below 1000 °C due to the nonuniform compositional distribution of the calcined powder. The homogeneous calcination at 950 °C for 2 h reduced greatly the optimum sintering temperature and significantly enhanced piezoelectric properties in the BF-BT ceramics. High Curie temperature as well as high piezoelectric properties were obtained at the sintering temperature as low as 920 °C: k p = 0.361, d 33 = 123 pC/N and T C = 653 °C in the 0.75BF-0.25BT ceramics and k p = 0.337, d 33 = 183 pC/N and T C = 525 °C in the 0.7BF-0.3BT ceramics. This low temperature sintering of the BF-BT ceramics by a homogeneous calcination could be applied to the fabrication of the lead-free multi-layer piezoelectric devices with inexpensive internal electrodes. [ABSTRACT FROM AUTHOR]

High‐temperature piezoelectric sensing is usually used in the aerospace, automotive, and power plant fields. High temperature piezoelectric ceramics are considered the key materials in these fields. In this paper, Ca1−x(Ba1/2Sr1/2)xBi2Nb1.985(W3/4Mn1/4)0.015O9 (x = 0.05, 0.10, 0.15 and 0.20) (C1−xBSxBNWM) has been synthesized by a traditional solid state reaction method. The effects of substitution of calcium at the A‐site by barium and strontium on phase evolution and piezoelectric properties of the CaBi2Nb2O9 orthorhombic Aurivillius phases were investigated. The crystal structure of piezoelectric ceramics was characterized by XRD, Rietveld refinement, and Raman spectroscopy. Co‐substitution of barium/strontium (Ba2+/Sr2+) and tungsten/manganese (W6+/Mn4+) resulted in lattice distortion of C1−xBSxBNWM ceramics. The results induce that the tetragonal crystal structure increase with increasing the co‐substitution cations. Isothermal impedance spectroscopy confirmed intrinsic thermally activated conduction in the system. The C1−xBSxBNWM ceramics with x = 0.15 exhibit a very high Curie temperature (TC ∼ 923°C), a reasonable piezoelectric coefficient (d33 = 13.3 pC/N). Remarkably, even after thermal annealing at temperatures up to 800°C, it still retains a high d33 of 13 pC/N. In addition, the C0.85BS0.15BNWM ceramic had a relatively high resistivity (3.82 × 106 Ω·cm, 500°C). The Ca0.85(Ba1/2Sr1/2)0.15Bi2Nb1.985(W3/4Mn1/4)0.015O9 ceramics make possible their application in high‐temperature acceleration transducers. [ABSTRACT FROM AUTHOR]

Traditional piezoelectric materials cause serious environmental and health issues because of their lead–containing substances, and thus lead–free piezoelectric ceramics would have many applications. In this study, we successfully prepared the lead–free ceramics (1- x) (K 0 · 48 Na 0 · 48 Li 0.04) (Nb 0 · 975 Sb 0.025)O 3 – x (Bi 0 · 5 Na 0.5) (Zr 0 · 8 Ti 0.2)O 3 ((1- x)KNLNS– x BNZT, x = 0, 0.005, 0.0075, 0.01, 0.015, 0.02 and 0.03) with rhombohedral–tetragonal (R–T) phase coexistence near room temperature, employing con–entional solid sintering. The minimum cell volume of the ceramics and R–T phase coexistence in them were achieved at a doping amount x = 0.01, which facilitated the optimal performance of the ceramics (d 33 ∼467 pC/N ± 14 pC/N, T c∼272 °C, ε r ∼1676, k p ∼0.42, where d 33 : piezoelectric constant; T c: Curie temperature; ε r : dielectric constant; k p : electromechanical coefficient). The ceramics exhibited microstructures with high density and low porosity and had a maximum relative density of 95.68 %. At x = 0.01, the ceramics exhibited a uniformly distributed small domain structures with nanodomains, accounting for their high-voltage electrical properties. Because these stable and reliable piezoelectric (1- x)KNLNS– x BNZT ceramics exhibit excellent electrical performance, they can replace lead–based materials. The direct solid–phase sintering method provides prospects for the large–scale application of the lead–free piezoelectric ceramics. The 0.99(K 0 · 48 Na 0 · 48 Li 0.04)(Nb 0 · 975 Sb 0.025)O 3 –0.01(Bi 0 · 5 Na 0.5)(Zr 0 · 8 Ti 0.2)O 3 ceramics exhibit excellent piezoelectric properties owing to their nanodomain structures, rhombohedral–tetragonal coexistence phase boundaries at room temperature (25°C ± 5°C) and dense microstructures. [Display omitted] [ABSTRACT FROM AUTHOR]

K0.5Na0.5NbO3 (KNN) crystals have great application prospects due to their excellent piezoelectric properties, high Curie temperature, and environmental friendliness. Currently, KNN crystals grown by the seed-free solid-state crystal growth (SFSSCG) method exhibit relatively high dielectric loss. In order to reduce their dielectric loss, Cu, Bi and Mn co-doped KNN lead-free piezoelectric single crystals were prepared by the SFSSCG method. The effects of the CuO doping content on the structure and electrical properties of (1 − x)(0.996KNN–0.004BiMnO3)–xCuO crystals were systematically studied. The results show that an appropriate doping amount of CuO is beneficial for the growth of the crystals and the improvement of electrical properties. When the diameter of the billets is 40 mm, the maximum crystal size of 25 × 21 × 2 mm3 is obtained. All crystals have a typical perovskite structure almost with a single orthorhombic phase and are very compact almost without holes. The minimum average domain width of 276 nm is obtained for the crystal at x = 0.005. The KNN crystals exhibit normal ferroelectric characteristics and a space-charge-limited-conduction (SCLC) mechanism. The introduction of Cu2+ ions reduces the dielectric loss of the crystal and increases its piezoelectric and dielectric properties. The Cu, Bi and Mn co-doped KNN crystals achieve excellent comprehensive properties: d33 = 314 pC N−1, Pr = 29.9 μC cm−2, Ec = 10.1 kV cm−1, = 869 pm V−1, Qm = 56.8, Kt = 0.38, tan δ = 0.013 and TC = 409 °C. This provides a route to improve the electrical properties of KNN-based crystals. [ABSTRACT FROM AUTHOR]

CaBi 2 Nb 2 O 9 (CBN) with the Aurivillius phase has a high Curie temperature (T C) and remarkable fatigue resistance, which has great potential for application as high-temperature sensors. However, due to its low piezoelectric properties, its practical application remains a great challenge. In this paper, Ca 1- x Ce x Bi 2 Nb 2 O 9 ceramics were prepared by the direct reaction sintering (DRS) and conventional preparation (CP) methods, respectively. The experimental results indicate that Ce doping can increase the piezoelectric coefficient d 33 of CBN ceramics by about two times. Among them, the grain size of the samples prepared by the DRS method is finer and more uniform, and the d 33 value of DRS samples is about 3.6–9.4 % higher than that of CP samples. The DRS sample Ca 0·97 Ce 0·03 Bi 2 Nb 2 O 9 has a d 33 value of 18.9 pC/N, a T C of 948 °C, and a resistivity of 1.1 × 105 Ω cm at 600 °C. This study shows that DRS method is an effective densification method, which can prepare CBN-based ceramics with excellent comprehensive properties, and provides an innovative preparation route to explore CBN-based ceramics with excellent piezoelectric properties. [ABSTRACT FROM AUTHOR]

Large piezoelectric voltage coefficient (g 33) and figure of merit (FOM 33) are the key parameters of perovskite ceramics for piezoelectric sensors and energy harvesters. Here, the Bi(Zn 2/3 Nb 1/3)O 3 (BZN) member with a low tolerance factor is introduced into the BiScO 3 -PbTiO 3 (BS-PT) perovskite high-temperature piezoelectric matrix to decouple the piezoelectric coefficient (d 33) and dielectric constant (ε r) by modulating the morphotropic phase boundary and grain size. For the optimal 0.38BS-0.01BZN-0.61PT ceramic that benefits from the decoupling of d 33 and ε r , its Curie temperature, g 33 and FOM 33 are as high as 436 °C, 38.6 mV·m·N−1 and 16.5×10−12 m2·N−1, respectively. Furthermore, the 0.38BS-0.01BZN-0.61PT ceramic also shows the technical advantages of large g 33 and FOM 33 even at harsh elevated temperatures (≥ 200 °C). Due to its outstanding comprehensive performances above, the 0.38BS-0.01BZN-0.61PT ceramic surpasses many other BS-PT-based piezoceramics. These results demonstrate that the 0.38BS-0.01BZN-0.61PT material is a promising competitor for high-temperature electromechanical coupling applications. • The BS-BZN-PT MPB ceramic has a high T C of 436 °C. • The variations of d 33 and ε r are decoupled in the BS-BZN-PT system. • The BS-BZN-PT MPB ceramic has a large g 33 of 38.6 mV·m·N−1. • The BS-BZN-PT MPB ceramic has a high FOM 33 of 16.5×10−12 m2·N−1. [ABSTRACT FROM AUTHOR]

Piezocatalysis is considered as an evolving technology based on the piezoelectric properties of catalysts, has shown great potential in the field of environmental remediation, water splitting, and biotechnology. In this work, the catalytic performance of (Ba0.95Ca0.05) (Ti1-xSnx)O3 (BCT1-xSx, 0.04 ≤ x ≤ 0.12) piezoelectric ceramics was studied systematically. The relationship between piezoelectric performance and piezo-photocatalytic performance was investigated. As the Sn content increased, the crystalline structure gradually changed from the orthorhombic (O) phase (x = 0.04) to O-pseudocubic (PC) two-phase coexistence (x = 0.08 and x = 0.10), and finally to the PC phase (x = 0.12). The piezoelectric constant d33 exhibited an initial increases followed by a decreases with rising Sn content, reaching peak of 509pC/N at x = 0.10. The enhanced d33 was due to multiphase coexistence and a Curie temperature near room temperature. The piezocatalytic efficacy of BCT1-xSx was linked to d33, with the maximum degradation rate achieved at x = 0.10. However, the optimal piezo-photocatalytic performance was obtained at x = 0.08 instead of x = 0.10 with the highest degradation rate of 69%. The photo-piezocatalytic performance was discovered to be intricately linked not only to the band gap of piezocatalysts but also influenced by their piezoelectric properties. These results will provide guidance for designing new lead-free piezoelectric materials with excellent catalytic properties. [ABSTRACT FROM AUTHOR]

To meet the current demand for lead-free piezoelectric ceramics, a novel sol-gel synthesis route is presented for the preparation of Ba0.85Ca0.15Ti0.9Zr0.1O3 doped with cerium (Ce = 0, 0.01, and 0.02 mol%) and vanadium (V = 0, 0.3, and 0.4 mol%). X-ray diffraction patterns reveal the formation of a perovskite phase (space group P4mm) for all samples after calcination at 800 °C and sintering at 1250, 1350, and 1450 °C, where it is proposed that both dopants occupy the B site. Sintering studies show that V doping allows the sintering temperature to be reduced to at least 1250 °C. Undoped BCZT samples sintered at the same temperature show reduced functional properties compared to V-doped samples, i.e., d33 values increase by an order of magnitude with doping. The dissipation factor tan δ decreases with increasing sintering temperature for all doping concentrations, while the Curie temperature TC increases for all V-doped samples, reaching 120 °C for high-concentration co-doped samples. All results indicate that vanadium doping can facilitate the processing of BCZT at lower sintering temperatures without compromising performance while promoting thermal property stability. [ABSTRACT FROM AUTHOR]

With the increasing demand for high-temperature piezoelectric ceramics, excellent piezoelectricity and high Curie temperature are required simultaneously. Herein, combining the advantages of constructing new-type solid solutions and traditional A-site doping strategy, Aurivillius ferroelectrics (Na0.5Bi0.5)0.5−x/2(Li0.5Ce0.5)x/2Bi2.5Ti0.5Nb1.5O9 (NBTN-LC100x, x = 0–0.16) were designed to achieve the large piezoelectric response and high Curie temperature simultaneously. The existence of a pseudo-tetragonal phase boundary together with the reduction of domain size produces a large piezoelectric coefficient (d33 ∼ 24.6 pC/N) with a fairly high TC (∼825 °C). Moreover, pseudo-tetragonal distortion might be responsible for the excellent thermal stability of d33 against thermal depolarization temperature (Td). For NBTN-LC12, high-temperature electric resistivity is still above 1 × 105 Ω cm at 600 °C. The improved comprehensive properties of NBTN-LC100x ceramics demonstrate that the construction of a novel Aurivillius ferroelectrics is a promising way to explore high-temperature sensor materials. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics working at high temperatures place high demands on the piezoelectric and insulating properties of the materials. Although CaBi 2 Nb 2 O 9 (CBNO) in bismuth layer-structured ferroelectrics (BLSFs) exhibits a rather high Curie temperature of 940 °C, its piezoelectric coefficient (d 33 ∼6 pC/N) and remanent polarization (P r ∼2 μC/cm2) are low. Here, we used a typical solid-state reaction approach to create strong textured piezoelectric ceramics CBNO with a Lotgering factor F 00l of 70% to improve the electrical characteristics of the material. The ferroelectric, dielectric, and piezoelectric properties perpendicular to the pressing direction were superior to those parallel to the pressing direction. Furthermore, the addition of V 2 O 5 can generate pseudo-tetragonal distortion in CBNO- x wt% V 2 O 5 ceramics, which has been shown to improve polarization switching and hence the piezoelectric capabilities of CBNO-based ceramics. As a result, the rather excellent electrical properties with a large d 33 of 21.5 pC/N, P r of 18.4 μC/cm2, and T C of 955 °C can be obtained simultaneously. Our results provide valuable guidance for the production of textured ceramics with exceptional overall performance in BLSFs. [ABSTRACT FROM AUTHOR]

In this manuscript, for the first time, the exploration of the microstructural, ferroelectric, piezoelectric, and dielectric performances are measured for Sm-ion-influenced pseudo-cubic, morphotropic phase boundary (MPB) regional 0.62BiFeO3−0.38SrTiO3:xwt%Sm2O3 (BFST:xSm) ceramics with x = 0–0.25. All the compositions maintained their pseudo-cubic MPB structural stability. The composition of BFST:0.15Sm ceramics exhibited an excellent remnant polarization (Pr) of ~52.11 μC/cm2, an enhanced d33 of 101 pC/N, and the highest relative dielectric constant (ɛr) of ~1152, which are much improved as compared to that of pure BFST ceramics. BFST:0.15Sm ceramics demonstrated a Curie temperature (TC) of 378 °C. Moreover, the composition exhibited high thermal stability for d33 72 pC/N (only a 28% decrease), even at a high temperature of 300 °C. Such outstanding outcomes make BFST:0.15Sm ceramics an ideal applicant for high-temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

Piezoelectric actuators are vital devices that convert electrical signals into mechanical strain, offering rapid and precise responses. Lead‐based piezoceramics have traditionally been the preferred choice for commercial piezoelectric actuators, while the low Curie temperature and the rising environmental concerns hinder their applications at high temperatures. In this study, a novel strategy is proposed to achieve high piezoelectric responses in lead‐free 0.67Bi1.05FeO3–0.33BaTiO3 (67BF‐33BT) ceramics with high Curie temperature by artificially generating a large internal bias field through repeat poling and aging treatments. A comprehensive exploration of how this internal bias field responds to applied electric fields and temperature variations has been conducted. The results suggest that the internal bias field originates from two aspects, one arises from the free charges that compensate for the depolarization field, while the other is attributed to the highly oriented defect dipoles. As a result of this internal bias field, the ceramics exhibit asymmetric strain–electric field (S–E) behaviors, resulting in a high strain (ε = 0.21%) and an extremely high piezoelectric coefficient (d33* = 1033.70 pm V−1) when subjected to low electric field (20 kV cm−1), along with good temperature stability from room temperature (RT) to 100 °C. [ABSTRACT FROM AUTHOR]

The enhanced and reliable high-power performance of x Pb(Mn 1/3 Nb 2/3)O 3 –(1- x)Pb(Zr 0.5 Ti 0.5)O 3 –0.5mol%Co 2 O 3 piezoelectric ceramics (x PMN–(1- x)PZT–Co; x = 0.04–0.10) has been achieved. It is noteworthy that the vibration velocity (υ 0) of the 0.08PMN–0.92PZT–Co ceramic reaches up to 0.9 m/s, which is 2.25 times that of commercial PZT4 ceramics (∼0.4 m/s). The high υ 0 of the 0.08PMN–0.92PZT–Co ceramic is attributed to its excellent electromechanical parameters: d 33 = 405 pC/N, Q m = 1405, and k p = 0.61. The 0.08PMN–0.92PZT–Co ceramic achieves a relatively low high-field tan δ (tan δ = 3.74% at 500 V/mm), thereby suppressing heat generation. Additionally, the significantly high Curie temperature (T c) value of 346 °C for the 0.08PMN–0.92PZT–Co ceramic stabilizes the ferroelectric phase. Therefore, the 0.08PMN–0.92PZT–Co ceramic exhibits long-term reliable high-power performance by maintaining a stable υ 0 of 0.9 m/s and slight temperature rise within 100 min. [ABSTRACT FROM AUTHOR]

As a typical perovskite‐like layered structure (PLS) ceramic, Sr2Nb2O7 (SNO) possesses a high Curie temperature TC value above 1300°C, which is expected to work in higher temperature environment. However, pure SNO presents a piezoelectric constant d33 value of ∼ 1 pC/N. Hence, (Li, Ce) ions are doped in SNO ceramics, which increases the distortion of oxygen octahedrons and enhances the intrinsic contribution of piezoelectric properties. The increased domain size with large proportion of high response areas means that the extrinsic contribution is also improved. The introduction of (Li, Ce) ions can also promote ceramic's grain growth and reduce oxygen vacancies, leading to the improvement of electrical properties. The optimal component Sr1.96(Li, Ce)0.02Nb2O7 ceramics exhibit a d33 value of 3.1 pC/N, a higher resistivity of 1.65×106 Ω·cm at 700°C and an excellent thermal stability (a d33 value of 3.0 pC/N after annealing at 1200°C for 2 h). This work provides an effective approach with simple process and low cost for the application of PLS materials in high‐temperature environments. [ABSTRACT FROM AUTHOR]

Currently, in the modification methods of K0.5Na0.5NbO3(KNN) ceramics to enhance their piezoelectric performance, key parameters such as Curie temperature are usually sacrificed. However, this trade-off limits the practical application of piezoelectric materials. Thus, addressing the trade-off between different performance parameters of piezoelectric ceramics becomes a major challenge.The present research employs the conventional solid phase sintering process and utilizes controlled doping of (Bi0.5Li0.5)0.9Sr0.1ZrO3 to regulate the ceramic system, K0.44Na0.55Ag0.01Nb0.95Ta0.05O3, at its polycrystalline phase boundary, thereby achieving a trade-off between performance. The ceramic samples of the system formed a compact solid solution with a single-phase perovskite structure and formed orthorhombic-tetragonal and rhombohedral-tetragonal polycrystalline phase boundaries at 0.02 ≤ x ≤ 0.03 and 0.035 ≤ x ≤ 0.06, respectively, according to XRD, SEM, and EDS analysis. The electrical properties test results show that in the multiphase coexisting region of x = 0.035, the ceramics of the system show excellent electrical properties, respectively d33 = 312 pC/N, kp = 46.5%, εr = 1019, tanδ = 3.78%, Pr = 20.08 μC/cm2, Ec = 12.97 kV/cm, and TC = 342 ℃. These results show that the properties of the system ceramics have reached a relatively high level, which provides an effective strategy for the practical application of piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Local domain evolution plays a vital role in modulating the high-temperature piezoelectricity of ferroelectric ceramics. Herein, 0.7BiFeO 3 -0.3BaTiO 3 - x Bi(Zn 0.5 Ti 0.5)O 3 (referred to as BF-BT- x BZT, 0.00 ≤ x ≤ 0.05) high temperature lead free piezoelectric ceramics were prepared by a solid-phase method. All ceramics are at the morphotropic phase boundary (MPB), with an overall decreasing trend of the R/Pc phase fraction upon heating. STEM reveals the in-situ heterogeneity of polar nanodomains. Due to the modulation with proper R/PC ratio and a multilayer nanodomain ratio, the in-situ d 33 and T dr values increase from 495 pC/N and 314 °C to 502 pC/N and 360 °C with increasing content of (Zn 1/2 Ti 1/2)3+ from x = 0 to x = 0.04 while maintaining a high Curie temperature (T c >470 °C). This study provides a new paradigm for studying the in-situ depolarization behavior of lead-free perovskite materials and to optimizing the high-temperature piezoelectric properties by tuning the domain scale. • Enhanced piezoelectric properties d 33 =502 pC/N when T dr =360 °C. • Unique domain structure in BF-BT ceramic. • Improved high-temperature piezoelectric tolerance related to nanodomains. [ABSTRACT FROM AUTHOR]

Lead-free piezoelectric ceramics 0.7BiFe 1- x (Zn 0.5 Sn 0.5) x O 3 -0.3BaTiO 3 [BF(ZS) x -BT] were successfully prepared using the solid-state reaction method. The dual effects of B-site Zn/Sn co-doping and quenching on the structure and piezoelectricity of BF(ZS) x -BT were investigated. All samples showed a distinct perovskite structure, characterized by the simultaneous presence of rhombohedral (R) and pseudo-cubic (pC) phases. The insulation and electrical properties were significantly increased by appropriate Zn/Sn co-doping and quenching treatment. The long parallel strip domains and enhanced lattice distortion synergistically contribute to the outstanding piezoelectricity (d 33 = 203 pC/N) and a high Curie temperature (T c = 493 °C) in quenched BF(ZS) 0.003 -BT. Furthermore, the quenching treatment was found to further improve the piezoelectric property and enhance its high-temperature stability, as demonstrated by the in-situ electromechanical coupling coefficient (k p) and thermal depolarization test. The d 33 of the quenched BF(ZS) 0.003 -BT was maintained at 186 pC/N around 400 °C, highlighting its promising applications in medium-high temperature conditions. [ABSTRACT FROM AUTHOR]

In this work, piezoelectric ceramics 0.125 Pb(Mg 1/3 Nb 2/3)O 3 -0.445PbZrO 3 -0.43PbTiO 3 + x mol% MnCO 3 (abbreviated as x Mn-PMN-PZT) were fabricated by the solid-state sintering method. The addition of MnCO 3 presented obvious changes in the phase structure, grain size, dielectric and piezoelectric performance. It was found that the doping of 2.5 mol% MnCO 3 can achieved the maximum mechanical quality factor Q m ∼1806 compared to the small Q m ∼96 for pure ceramics. Meanwhile, a moderate piezoelectric coefficient d 33 ∼ 260 pC/N and a high Curie temperature T c ∼325 °C were also achieved in 2.5Mn-PMN-PZT ceramics. These excellent properties were close to the hardening effect of MnCO 3 and the formation of defect dipoles in the MC-PMN-PZT ceramics. [ABSTRACT FROM AUTHOR]

CaBi2Nb2O9 ceramics were fabricated via the solid-state reaction method by the addition of B2O3 as a sintering aid at lower sintering temperatures than that prepared without B2O3. Ferroelectricity, piezoelectricity, and resistivity can be still greatly enhanced when the sintering temperature is decreased from 1075 °C for CaBi2Nb2O9 to 975 °C for CaBi2Nb2O9–0.25 wt. % B2O3. The high resistivity and weak c-axis texture ensure that the ceramics can be fully polarized in a high enough electric field. The increased spontaneous ferroelectric and remanent polarization result in a significant enhancement in the piezoelectric properties of CaBi2Nb2O9–0.25 wt. % B2O3. The sample sintered at 975 °C possesses a high piezoelectric coefficient d33 of ∼15.0 pC/N and resistivity of 1.4 × 106 Ω cm (at 600 °C) along with a high ferroelectric Curie temperature TC of ∼954 °C. This work is beneficial for the preparation of high-temperature piezoelectric ceramics with excellent electrical properties at a low sintering temperature. [ABSTRACT FROM AUTHOR]

CaBi2Nb2O9 ceramics were fabricated via the solid-state reaction method by the addition of B2O3 as a sintering aid at lower sintering temperatures than that prepared without B2O3. Ferroelectricity, piezoelectricity, and resistivity can be still greatly enhanced when the sintering temperature is decreased from 1075 °C for CaBi2Nb2O9 to 975 °C for CaBi2Nb2O9–0.25 wt. % B2O3. The high resistivity and weak c-axis texture ensure that the ceramics can be fully polarized in a high enough electric field. The increased spontaneous ferroelectric and remanent polarization result in a significant enhancement in the piezoelectric properties of CaBi2Nb2O9–0.25 wt. % B2O3. The sample sintered at 975 °C possesses a high piezoelectric coefficient d33 of ∼15.0 pC/N and resistivity of 1.4 × 106 Ω cm (at 600 °C) along with a high ferroelectric Curie temperature TC of ∼954 °C. This work is beneficial for the preparation of high-temperature piezoelectric ceramics with excellent electrical properties at a low sintering temperature. [ABSTRACT FROM AUTHOR]

The development of high-performance lead-free K0.5Na0.5NbO3-based piezoceramics for replacing commercial lead-containing counterparts is crucial for achieving environmentally sustainable society. Although the proposed new phase boundaries (NPB) can effectively improve the piezoelectricity of KNN-based ceramics, the difficulty of achieving saturated poling and the underlying multiscale structures resolution of their complex microstructures are urgent issues. Here, we employ a medium entropy strategy to design NPB and utilize texture engineering to induce crystal orientation. The developed K0.5Na0.5NbO3-based ceramics enjoys both prominent piezoelectric performance and satisfactory Curie temperature, thus exhibiting an ultrahigh energy harvesting performance as well as excellent transducer performance, which is highly competitive in both lead-free and lead-based piezoceramics. Comprehensive structural analysis have ascertained that the field-induced efficient multiscale polarization configurations irreversible transitions greatly encourages high saturated poling. This study demonstrates a strategy for designing high-performance piezoceramics and establishes a close correlation between the piezoelectricty and the underlying multiscale structures. There are difficulty of achieving saturated poling and understanding of multi-scale structures in (K, Na)NbO3 ceramics. Here, the authors find atomic-scale polymorphic distortion and micrometer-scale high-density thin striped domains, which is key for high saturated poling. [ABSTRACT FROM AUTHOR]

Piezoelectric thin films are extensively used as sensing or actuating layers in various micro-electromechanical systems (MEMS) applications. However, most piezoelectrics are stiff ceramics, and current polymer piezoelectrics are not compatible with microfabrication due to their low Curie Temperature. Recent polymer-composite piezoelectrics have gained interest but can be difficult to pattern. Photodefinable piezoelectric films could resolve these challenges by reducing the manufacturability steps by eliminating the etching process. But they typically have poor resolution and thickness properties. This study explores methods of enhancing the manufacturability of piezoelectric composite films by optimizing the process parameters and synthesis of SU-8 piezo-composite materials. Piezoelectric ceramic powders (barium titanate (BTO) and lead zirconate titanate (PZT)) were integrated into SU-8, a negative epoxy-based photoresist, to produce high-resolution composites in a non-cleanroom environment. I-line (365 nm) light was used to enhance resolution compared to broadband lithography. Two variations of SU-8 were prepared by thinning down SU-8 3050 and SU-8 3005. Different weight percentages of the piezoelectric powders were investigated: 5, 10, 15 and 20 wt.% along with varied photolithography processing parameters. The composites' transmittance properties were characterized using UV-Vis spectroscopy and the films' crystallinity was determined using X-ray diffraction (XRD). The 0–3 SU-8/piezo composites demonstrated resolutions < 2 μm while maintaining bulk piezoelectric coefficients d33 > 5 pm V−1. The films were developed with thicknesses >10 μm. Stacked layers were achieved and demonstrated significantly higher d33 properties. [ABSTRACT FROM AUTHOR]

(K0.5Na0.5)NbO3 (KNN)-based ceramics have been extensively investigated as replacements for Pb(Zr, Ti)O3-based ceramics. KNN-based ceramics exhibit an orthorhombic structure at room temperature and a rhombohedral–orthorhombic (R–O) phase transition temperature (TR–O), orthorhombic–tetragonal (O–T) phase transition temperature (TO–T), and Curie temperature of −110, 190, and 420 °C, respectively. Forming KNN-based ceramics with a multistructure that can assist in domain rotation is one technique for enhancing their piezoelectric properties. This review investigates and introduces KNN-based ceramics with various multistructures. A reactive-templated grain growth method that aligns the grains of piezoceramics in a specific orientation is another approach for improving the piezoelectric properties of KNN-modified ceramics. The piezoelectric properties of the [001]-textured KNN-based ceramics are improved because their microstructures are similar to those of the [001]-oriented single crystals. The improvement in the piezoelectric properties after [001] texturing is largely influenced by the crystal structure of the textured ceramics. In this review, [001]-textured KNN-based ceramics with different crystal structures are investigated and systematically summarized. [ABSTRACT FROM AUTHOR]

In this study, the Pb(Yb 1/2 Nb 1/2)O 3 (PYN) relaxor with high Curie temperature (T C ∼300 °C) was incorporated into PbZrO 3 -PbTiO 3 (PZ-PT) ceramics to form 0.1PYN-(1- x)PZ- x PT ternary ceramics, and their phase compositions were systematically investigated, providing the more detailed phase diagrams, dielectric, piezoelectric, and ferroelectric properties. Excellent piezoelectric performance (d 33 ∼ 450 pC/N, d 33 * ∼714 pm/V), with high coercive field (E C ∼17.5 kV/cm) and T C (∼398 °C) were simultaneously achieved in the 0.1PYN-0.41PZ-0.49PT composition near the morphotropic phase boundary (MPB). The value of d 33 × E C , which exhibits higher than commercial PZT ceramics, indicates its suitability for high-field excitation devices. Additionally, the temperature stability of the resonant frequency (f r) is qualitatively studied by analyzing the main factors influencing f r from a theoretical perspective. Superior stability is achieved in the 0.1PYN-0.38PZ-0.52PT composition (T C ∼ 405 °C) with tetragonal phase, and the temperature coefficient of resonant frequency (Δ f r / f r 25 °C) remains within 0.5% up to 300 °C, far outperformance than previous reports. [ABSTRACT FROM AUTHOR]

Having the distinction of being one of the most extensively employed piezoelectric ceramic materials worldwide and multi-faceted, lead zirconate titanate (PZT) has numerous applications and characteristics. In 1954, a remarkable discovery happened at the Tokyo Institute of Technology, which was the development of PZT. Due to its excellent dielectric constant, piezoelectric value, polarization, high Curie temperature, and flexibility, it has been widely used in the field of mechanical engineering, along with other branches of sciences. The main interest of this review article is to describe the significance and involvement of PZT in the field of mechanical engineering. This article starts with a brief review of the history of PZT, after that different synthesis methods, and applications of PZT in relevance to the field of mechanical engineering have been discussed. Finally, this article concludes with the future scope of PZT in the field of mechanical engineering. [ABSTRACT FROM AUTHOR]

Hard piezoelectric properties are investigated in lead‐free BiFeO3–BaTiO3 (BF–BT) ceramics. Rhombohedral (R) phase ceramics of (1 – x)BF–xBT (x = 0.20–0.30) were prepared using a conventional solid‐state reaction and water‐quenching process. The R structure is observed in x = 0.20–0.275, and the R and tetragonal phases coexist at x = 0.30. The piezoelectric charge sensor coefficient (d33) and electromechanical planar coupling factor (kp) increase with increasing BT content, whereas the mechanical quality factor (Qm) decreases. The x = 0.20 ceramic shows the best hard piezoelectric properties: the highest Qm = 403 and the highest TC = 607°C. In contrast, x = 0.30 ceramic shows soft piezoelectric properties: d33 = 301 pC/N and kp = 0.33 with TC = 510°C. These results show that the BF–BT system in R‐phase‐rich region has good hard piezoelectric properties for transducer applications. [ABSTRACT FROM AUTHOR]